The present invention relates to a mechanical linkage which may be employed in a gauge to average displacements at a plurality of locations along the irregular surface of an object. The linkage arrangement also results in substantially equal force being applied to the object so that an equal force clamp may be constructed.
Gauges are known having probes for contacting irregular surfaces of an object with an output indicating the average of the individual probe displacements. Such gauges are often used for classifying vane airfoils so that turbine wheels can be built up having appropriate vane throat areas. One known gauge operates on a hydraulic principle to average probe displacements. Generally, flexible diaphragms with an unsupported section provide an interface between the probe and a fluid reservoir. The hydraulic gauges, while quite accurate, are temperature sensitive potentially resulting in errors with ambient temperature changes. Other classification gauges are known using "whiffles" or probes whose orientations are utilized for object classification.
It is therefore an object of the present invention to provide a gauge which eliminates the drawbacks of the known hydraulic gauges.
A further object of the invention is such a gauge which is highly accurate and substantially wear resistant resulting in a high degree of measurement repeatability.
A still further object of the invention is a mechanical linkage arrangement which provides equal force at each probe contact point for use in clamping.